Dehydrogenation of hydrocarbons



Patented May 1, 1945 I i 2 314 932 UNITED STATES PATENT oer-les- Walter R. r. Guyer, Elisabeth, NIL, aaainor a Standard Oil Development Company,- a corporation ol-Delawarc No Drawing. Application November 15,1941,

1 Serial No. uazss 11 Claims. (Cl. 260-.880)

- This invention relates to the catalytic dehy aiuminumoxide, aminor proportional vanadium s nation. of hydrocarbons of low molecular oxide and a small amount of silver. The Press for example those having from 2' to ence of small amounts of or-potsssium." carbon atoms, and is more particularly conoxide is also beneficial in some cases. The cata cerned with improvedmethods or operation and 5 lyst may consist, for examplqoi 77 to 93% by improved catalysts torusetherein. weight of aluminum oxide,- 545% 'by'welzht oi Typical oi processes for the catalytic dehyvanadium-oxideand 243% by weight 0! silver.

' drogenation' 01' low molecular .weisht -hydrocar- An especially eilective catalyst of this type has bons are processes for converting butane to buthe following app wmpwtiimif tene and processes for convertingbutene to bul0 tadiene. Both butene and butadiene are raw materials for the preparation of other products. I cmmmm Percent by weidht )For example, butene isan essential raw material inalkylation processes for the production or isc- I M octane or other high octane number hydrocar- 2 bons for use in or as motor fuels; isobutene is Y an essential .raw material for the preparation of I a. isobutylene polymers 01' various molecular one meal preparing a catalyst having weights; and butadiene is an essential raw majust'glvenis muows:

terial fo'r'the production of synthetic rubbers 1860 grams alumium hydmxide such asBuna-N and -s is rolled in a ball mill for about six hoursv to- In the production of olefln's and diolenns by gather with 20 grams Vanadium Oxide- 10 the catalytic dehydrogenation of paramns and Emma of silver oxide and 150 cc. ot ammoniumoleflns respectively, it is of course desirable to hydroxide. The silver oxide is prepared by addbt m -m yield of the olefin or di l fln g5 ing'10% sodium hydroxide solution to 15.8 grams as ible on o passe. of'silver nitrate. The thoroughly mixed ingrethr o uz h the detailwa f; m igg zfgfi dients are then dried .and heated to a temperaas small-an amount as possible of by-product ture oi! 1200* F. The catalystso prepared may It is also desirable to conduct the dehydrogenabe molded shaped P tablets or Pieces tion under such conditions and in the presence any desired shape and size It y be of such. catalysts that the formation of coke aimed fine Powder- The m which the m on the catalyst is reduced to a minimum. The catalyst is'pmpared Wm of course depend efllciency of theeatalyst b t measured in terms whether it is to be used in fixed or stationary of percent selectivity by which i t't form or in ilnely divided form suspended in the cent of the total amount of lmtial material unvapors. of the ys mto be dehydro- 80 g conversion which is converted to the 'Benateddesired dehydrogenated product. For exam l v Assuming the-catalyst is to be used in staif 50% or the initial material undergoes n r; 1 tionary form, a sui a mtiqh chamberis filled s'ion in the reaction zone-and-30%,of the initial with bil s o P n P 0! h catalyst tc c. material consists oi the desired dehydrosenated m d wi h a e ts steam. n s product, then the percent selectivity would be 60, methane. flu 8 d t e like i th n P ss -I have foundanew type of catalyst h, through-the reaction chamber at a rate between when used under certain conditions in the cata- 100 and. 5000, refera y between 9 a d 200 lytic dehydrogenation of low molecular weight volumes (measured at normaltemperature and hydrocarbonsmakesit possible'to obtain subpressure): otr'putejne perivolume of catalyst per stantially greater yields of the desired dehyhour. -'Ihe.paitial. pressure of butane in the re:

drogenated product than cau be obtained by the i n cham er 1 P ferab y in ai use or known catalysts. The nature tween 80 and 200 of mercury.- This'partial of the new catalysts and the conditions under I pressur'may be obtained by dilution of the buwhich they are. used will be fully understood from tene with the type. of diluents mentioned above. the following description: 4 y For purposes-or description it will beassumed uum, or by acombinatlon of both means. that it is desired to prepare butadieneeby the 'I'hereaction chamber is maintained at a tem-I catalytic'dehydroaenation of butene. .The cataventure between 1000' and 1600 1, preferably lystto beused comp'rlsesa major proportion er 9 must and mo r., and under atmos 4 by maintaining the reaction chamber undervvac of aluminum oxide, a minor proporti pheric pressure or under vacuum. The b'utene which passes through the reaction chamber unaffected may of course be recycled thereto together with additional diluent.

.It will be found that after a period of 3 to 20 hours or more, the formation or deposition of coke on the catalyst will have reduced its activity to such an extent that a regeneration treatof the catalyst mass during regeneration should be maintained between about 1000 and 1200 F.

The following example illustrates the applicadrogenation of hydrocarbons having from 2 to 5 carbon atoms which comprise passing said hydrocarbons under a partial pressure of between 80 and 200 mm. of mercury and at a temperature between 1000 and 1600 F. over a catalyst comprising between 77 and 93% by weight of aluminum oxide, 5 and by weight of vanadium oxide and. 2 and 8% by weight of silver.

3. An improved process for the catalytic dehydrogenation of low molecular weight hydrocarbons which comprises diluting said hydrocarbons with an inert gas to reduce the partial pressure of said hydrocarbons in the mixture to between 80 and 200 mm. of mercury and passing the mixture at a temperature between 1000 and 1600 F. over a catalyst consisting of a major i proportion of aluminum oxide, aminor proportion of the process to the production of butadiene 7 from butene:

Butene, at a reduced pressure of about 97 mm. of mercury, is passed through a reaction chamber maintained at a temperature of 1191 F. and containing a catalyst consisting of 85% by weight of aluminum oxide, 10% by weight of vanadium oxide and 5% by'weight of silver at a rate of about 482 volumes of butene (measured at normal temperature and pressure) per volume of catalyst per .hour for a period or 3 hours. The following results are obtained:

Total butene converted mol per cent..- Butadiene 35-.0 Coke do 8.9 CO o 0.71 Percent selectivity 70.0

It will be seen that 35 mol per cent of the butene is converted'to butadiene with a percent selectiviw'of 70.

While the process has been described with particular reference to the production of butadiene from butene when using a fixed catalyst. it will be understood that it'is equally applicable to the dehydrogenation of other low molecular weight tion of vanadium oxide and a small amount of silver.

4. An improved process for the catalytic dehydrogenation of low molecular weight hydrocarbons which comprises passing said hydrocarbons at a pressure between 80 and 200 mm. of mercury and at a temperature between 1000 and 1600- F. over a cata yst consisting of a major proportion of aluminum oxide, a minor'proportion of vanadium oxide'and a small amount of silver.

5. An improved process for the dehydrogenation of a hydrocarbon having 4 carbonatoms which comprises passing said hydrocarbon under a partial pressure between 80 and 200 mm of mercury and at a temperature between 1000 and 1600 F. over a catalyst consisting of a major '40 partial pressure of the hydrocarbon is reduced to parafiins or oleiins and that the catalyst may 'beused in finely divided form.

This invention is not limited by any theories of the mechanism of the reactions nor by any details which have been given merely for purposes of illustration but is limited only in and by thefollowing claims in which it is intended to claim all novelty inherent in the invention.

I claim: a

1. An improved process for the 'catalytic dehydrogenation of low molecular weight hydrocarbons which comprises passing said' hydro carbons at a temperature between 1000 and 1600 F. over a catalyst comprising a. major proportion f vanadium oxide and a small amount of ver. Y 2. An-improved process for the catalytic dehyproportion of aluminum oxide, a minor proportion of vanadium oxide and a small amount of silver. i

6. Process according to claim 5 in which the hydrocarbon is passed over the catalyst at a temperature between 1100 and 1300 F.

'7. Process according to claim 5 in which the between and 200mm. of mercury by diluting it with steam. 4

8. Process according to claim 5 in which the catalyst consists of between 7'7 and 93% by weight of aluminum oxide, between 5 and 15% by weight of vanadium oxide, and between 2 and 8% by weight of silver. 1 9. Process according to claim 5 in which the hydrocarbon of 4 carbon atoms is butene.

10. Process according to claim 5 in which the catalyst comprises by weight of aluminum oxide, 10% by weight of vanadium oxide and 5% by weight of silver.

11. Process for converting tial pressure between 80 and 200 mm. of mercury and at a temperature between 1100 and 1300" F.

.ovena catalyst consisting of a major proportion WALTER R. F. GUYER.

butene to butadie e which comprises passingthe butene under a pa 

